Condensed Matter Seminar

Markus Mueller
University of Geneva

Thursday, November 20, 2008
1:00 pm in SPL 52

Relativistic magnetotransport in graphene

Abstract: The electrons and holes in a single graphene sheet behave very much like a relativistic liquid. I will discuss the peculiarities of thermo-electric transport of this fluid of interacting Dirac fermions using Boltzmann transport theory. At small doping and high temperatures, graphene has many signatures of a quantum critical system where the inelastic scattering rate is set only by the temperature, and the conductivity assumes a universal value due to electron-hole friction. In this regime we find pronounced deviations from Fermi liquid behavior, such as significant enhancements of the Mott and Wiedemann-Franz ratio, as well as a peculiar collective cyclotron resonance in the presence of a magnetic field, with an intrinsic, collision-induced width. Some of these results have been anticipated by a simple but elegant relativistic hydrodynamic theory which are fully confirmed in the appropriate limit of Boltzmann transport theory. I will also show that undoped graphene is a nearly ideal fluid in the sense that its viscosity is anomalously small and almost saturates the lower bound conjectured from holographic mappings to black holes.